Furnace



(No' Model.)

L.P.'FRENCH.

' FURNAGE. v I No. 299,974: v Paten tedJune10,18'84. V

UNTTED grains PATENT @rrrcze,

LYMAN P. FRENCH, OF BOSTON, MASSACHUSETTS.

FURNACE.

M SPECIFICATION forming part of Letters Patent No. 299,974, dated June10, 1884.

Application filed October 9.6, 1883: (No model.)

To aZZ whom, it may concern.-

Be it known that I, LYMAN P. FRENCH, of Boston, county of Suffolk, Stateof Massachusetts, have invented an Improvement in Furnaces, of which thefollowing description, in connection with the accompanying drawings, isa specification, like letters on the drawings representing like parts.

My invention relating to furnaces is shown embodied in a locomotivefire-box or furnace having an inclined bridge-wall extending diagonallyacross the fire-box from its lower front end toward its rear upper end,the furnace also having a deflecting-wall depending from its crown-sheetin front of the upper edge of the bridgewall.

In another application for Letters Patent No. 95,125, filed May 16,1883, I have shown and described a furnace having walls of this generalarrangement, the bridgewall, however, being partly composed of awater-space or table which is necessarily a permanent part of thefire-box, and is very expensive.

The present invention consists in a novel construction of thebridge-wall, which is of masonry, and is made hollow for the introduction of heated air.

Masonry walls for the introduction of air have usually been made ofhollow bricks provided with numerous small perforations for the air toflow through; but such construction is very objectionable, as owing tothe great difference in temperature of the different parts of the bricksthey expand unequally and soon break or crumble, and furthermore thearea of heatingsurface to which the air is exposed is reduced by theperforations.

Arches or walls for the introduction of air have also been made offire-brick having a single large air passage or chamber within them, andof two layers of brick having corresponding grooves in their adjacentfaces which constitute a seriesof tubular passages passinglongitudinally through the wall. In this latter construction the mainpart of the two layers are in contact with one another, forming a solidmass of masonry. When the wall has a large space or chamber includedwithin it, and the faces of the brick inclosing the said space areseparated from one another and unequally exposed to the fire, as isusually the case, one

side, for example, being exposed directly to the fire, and the otherprotected therefrom by the intervening layer of air, the said faces ofthe brick will be unequally heated and the greater expansion of the onethan of the other will produce severe internal strains, which will soonresult in the destruction of the brick and arch constructed therefrom.These objections are obviated in the present invention by making thewall of two independent layers of bricks separated a sufficient distanceto inclose between them an air space or chamber of the desired size,thesaid chamber opening at the'end of the wall directly into thefirebox. The separation of the layers is preferably effected byproviding them with laterallyprojecting flanges, which are turned upwardin the lower layer and downward in the upper layer, the latterlying 011the former. Each layer being quite thin but of uniform thicknessthroughout, will attain substantially uni form temperature throughout,and the two layers being disconnected from one another, the one next thefire, which will reach the highest temperature, is free to expand orcrawl along the other without producing any strain, so that a wall orarch'constructed in this manner is very durable.

Figure 1 is a longitudinal section of a locomotive firc-box embodyingthis invention. Fig. 2 is a horizontal section thereof on line as as;Fig. 3, a perspective view of one of the bricks of which the arch orbridge-wall is composed.

The firebox a, grate b, and opening a, for the introduction of fuel, areall of usual construction, being as found in locomotives now in use. Thesaid fire-box contains an arch or bridge-wall, e c, composed of twoindependent layers of firebrick, shown in this instance as supported onwater-pipes 2', connected by suitable couplings with the sheets of thefirebox. The lower layer, e, of brick rests direct- 1y on the saidpipes, and the upper layer, 6', is supported a short distance above thelower layer, thus inclosing an air space or chamber between them,provided with inlet-passages on through the walls of the fire-boxconnecting with the external atmosphere and admitting air to the spacesbetween the two parts of the bridge-wall. As herein shown, the upperportion of the bridge-wall is supported above the lower portion, 6, bymeans of corresponding flanges, 6 on the two layers of brick,

and the upper edge of the air-chamber in the' ward and upward directionto a point a short tension over the door.

distance below the crown-sheet, and the firebox is also provided with adeflecting-wall, m, extending from the crown-sheet forward and downwardtoward the bridge-wall, the lower edge of the said deflecting-wall beingin front of and below the level of the upper edge of the bridge-wall. Inthe said application, however, the bridge-wall was shown as having anextension reaching the rear sheet above the door, so that the productsof combustion were compelled to pass through two passages, one at eitherside of the door. The said ex tension was intended to protect the finesfrom access of cold air when the door was opened for the introduction offuel, and the claims of the said application cover, broadly, thecombination of the bridgewall and deflecting-wall having the describedarrangement with relationto one another, independently of the ex- It isoften found to be more advantageous to afford a uniform passage for theproducts of combustion over the entire upper edge of the bridge-wallthan to provide for the protection of the dues when the door is opened,and in the present application the upper edge of bridge-wall issubstantially parallel with the crown-sheet, thereby affording a uniformpassage for the products of combustion over the entire upper edge.

I do not in the present application broadly claim the combination of thebridge'wall and deflecting-wall, nor a bridgewall provided with anair-chamber.

I claim 1.. In a furnace, a bridge-wall or arch com= posed of twoindependentthin layers of unperforated fire-brick, each layer being ofsubstantially uniform thickness throughout, and the layers beingseparated from between them, the said chamber communicating with the airoutside of the furnace and opening at one end of the layers of brickinto the furnace, substantially as described.

2. The bridge-wall inclined from the lower front wall of the fire-boxrearwardly and up.- wardly, the said wall being composed of twoindependent layers of bricks, each layer being of substantially uniformthickness, and the two layers being separated by an air-space, whichopens into the furnace at the upper edge of the wall and communicateswith the air external to the furnace at the lower portion of the saidwall, substantially as described.

3. The bridge-wall inclined from the lower front wall of the fire-boxrearwardly and up wardly, the said wall being composed of two layers ofbricks separated by an air-space which opens into the furnace at theupper edge of the wall and communicates with the air at the outside ofthe furnace at the lower portion of the said wall, combined with thedeflecting-wall depending from the crownsheet in front of the upper edgeof the said bridge-wall, the lower edge of the said deflect ing-wallbeing below the level of the upper edge of the said bridgewall,substantially as described.

4. Thebridge-wallextendingfromthelower front portion of the fire-boxbelow the fines rearwardly and upwardly toward the crownsheet, the upperedge of the said wall being substantially parallel with the crown-sheet,combined with the deflecting-wall, depending from the crownsheet in aninclined forward and downward direction, and having itslower edgeparallel with and below the level of the upper edge of the bridge-wall,substantially as described.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

LYMAN P. FRENCH.

\Vitnesses:

Jos. P. LIVERMORE, V. H. SIcs'roN.

